Technology reduces the risk of untreated water discharge

In a first for the Southern Hemisphere, Citycare Water is using the latest technology to pinpoint temperature changes in water networks and reduce the risk of untreated water being discharged into the environment.

Temperature profiling in wastewater pipes can help water infrastructure owners identify where stormwater is leaking in their sewer networks and vice versa, which is valuable information generated by Citycare Water’s cutting-edge technology.

Distributed Temperature Sensing Technology, or DTS, is in operation in Kaiapoi for the Waimakariri District Council and Collingwood presently for the Tasman District Council.

Citycare Water Digital Networks Field Engineer Kieran Scott is an expert in the deployment of IoT devices (technology run on the internet of things) and explains how DTS works.

“The DTS device is located in a trailer and skilled installers temporarily lay fibre-optic cable at the bottom of water pipes, where pulses of light travel along the length of the cable.

“A small amount of light is backscattered and returns to the DTS instrument.

“The temperature of the optical cable is calculated from changes in wavelength of the backscattered light.

“By measuring the time, it takes the backscattered light to return, the DTS instrument can also measure the location of the event to within a metre.”

The fibre-optic cable is installed in the network, then left in place for the monitoring period before being fully removed once enough data has been collected.

Kieran says the data enables the team to monitor and analyse wet and dry weather inflow and infiltration to accurately pinpoint all inflow from rain and surface water and infiltration from groundwater.

“This enables us to detect both the transient and chronic water entry points into the network,” commonly known as leaks due to groundwater seepage or the stormwater and wastewater pipes being overloaded, he says.

The next location for installation of the DTS is in Duvauchelle, Akaroa Harbour, for the Christchurch City Council.

Matt Dyer and Kevin Pretty installing the Distributed Temperature Sensing Technology in Collingwood, at the northern tip of the South Island, for the Tasman District Council.